Frost dates for 21701Frederick, MD
The average last spring frost in Frederick is April 2 and the average first fall frost is November 6, giving a typical growing season of about 218 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 2
- Average first fall frost
- Nov 6
- Growing season
- 218 days
Safer after Apr 15 (1-in-10 risk)
Possible by Oct 23 (1-in-10 risk)
First frost typically in 3 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | Mar 31 · Apr 15 · May 2 | Oct 9 · Oct 24 · Nov 6 | 193 days | 100% |
| Frost / freeze (32°F) | Mar 17 · Apr 2 · Apr 15 | Oct 23 · Nov 6 · Nov 24 | 218 days | 100% |
| Hard freeze (28°F) | Mar 3 · Mar 21 · Apr 4 | Nov 6 · Nov 21 · Dec 11 | 245 days | 100% |
Planting calendar for Frederick
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Mar 2 – May 8 |
| Tomatoes | Transplant outdoors | Apr 18 – Jul 17 |
| Peppers | Start seeds indoors | Mar 2 – Apr 2 |
| Peppers | Transplant outdoors | May 2 – Jun 2 |
| Eggplant | Start seeds indoors | Mar 19 – Apr 17 |
| Eggplant | Transplant outdoors | May 2 – Jun 2 |
| Cucumbers | Sow outdoors | May 2 – Jul 27 |
| Summer squash | Sow outdoors | Apr 18 – Jun 2 |
| Winter squash & pumpkins | Sow outdoors | May 2 – Jun 2 |
| Snap beans | Sow outdoors | Apr 18 – Aug 19 |
| Sweet corn | Sow outdoors | Apr 18 – Jul 17 |
| Watermelon & cantaloupe | Sow outdoors | May 2 – Jun 2 |
| Okra | Sow outdoors | Apr 25 – May 18 |
| Peas | Sow outdoors (spring) | Mar 2 – Apr 17 |
| Potatoes | Plant outdoors (spring) | Mar 2 – May 2 |
| Onions | Start seeds indoors (spring) | Jan 19 – Feb 15 |
| Onions | Transplant outdoors (spring) | Mar 19 – Apr 17 |
| Broccoli | Start seeds indoors (spring) | Feb 12 – Mar 18 |
| Broccoli | Transplant outdoors (spring) | Mar 19 – Apr 17 |
| Broccoli | Start seeds indoors (fall) | Jul 7 – Jul 17 |
| Broccoli | Transplant outdoors (fall) | Aug 6 – Aug 17 |
| Cabbage | Start seeds indoors (spring) | Feb 2 – Mar 2 |
| Cabbage | Transplant outdoors (spring) | Mar 2 – Apr 2 |
| Cabbage | Start seeds indoors (fall) | Jun 27 – Jul 27 |
| Cabbage | Transplant outdoors (fall) | Jul 27 – Aug 27 |
| Leaf lettuce | Sow outdoors (spring) | Mar 2 – May 18 |
| Leaf lettuce | Sow outdoors (fall) | Jul 27 – Sep 12 |
| Spinach | Sow outdoors (spring) | Feb 23 – Apr 8 |
| Spinach | Sow outdoors (fall) | Aug 13 – Sep 17 |
| Radishes | Sow outdoors (spring) | Mar 2 – Apr 22 |
| Radishes | Sow outdoors (fall) | Jul 27 – Sep 27 |
| Kale | Sow outdoors (spring) | Mar 19 – Apr 8 |
| Kale | Sow outdoors (fall) | Jul 20 – Aug 27 |
| Carrots | Sow outdoors (spring) | Apr 2 – May 18 |
| Carrots | Sow outdoors (fall) | Jun 27 – Aug 12 |
| Garlic | Plant outdoors (fall) | Oct 27 – Nov 27 |
Where these dates come from
ZIP code 21701 is matched to the NOAA station Frederick Police Brks, MD, 9.5 km away, at 380 ft elevation (17 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Frederick Police Brks, MD (used) | 380 ft | Apr 2 | Nov 6 |
| Damascus 3 Ssw, MD | 700 ft | Apr 14 | Oct 29 |
| Catoctin Mtn Park, MD | 1,610 ft | Apr 14 | Oct 30 |
| Emmitsburg 2 Se, MD | 403 ft | Apr 22 | Oct 20 |
Frost dates near Frederick
- Walkersville, MD 21793 · last Apr 22, first Oct 20
- Frederick, MD 21709 · last Apr 2, first Nov 6
- New Market, MD 21774 · last Apr 14, first Oct 29
- Libertytown, MD 21762 · last Apr 22, first Oct 20
- Woodsboro, MD 21798 · last Apr 22, first Oct 20
- Monrovia, MD 21770 · last Apr 14, first Oct 29
- Unionville, MD 21792 · last Apr 22, first Oct 20
- New Midway, MD 21775 · last Apr 22, first Oct 20
Frequently asked questions
- When is the last frost in Frederick, MD?
- For ZIP code 21701, the average last spring frost (32°F) is April 2, based on NOAA 1991-2020 climate normals for the Frederick Police Brks, MD weather station. There is a 1-in-10 chance of a frost after April 15.
- When is the first frost in Frederick, MD?
- The average first fall frost (32°F) is November 6. There is a 1-in-10 chance of frost by October 23, so tender plants are at risk from that point on.
- How long is the growing season in 21701?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 218 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.